Generally speaking, a linearly actuated pump includes a drive assembly operatively engaged with a pumping assembly. The pumping assembly generally includes a barrel having a bore extending therethrough, a head having a chamber for pressurization of a fluid, and a pump plunger positioned within the bore. The drive assembly provides reciprocating linear motion to the pump plunger, thereby causing it to reciprocate within the bore.
While the pump plunger is moving in a pressurization stroke or pumping direction, at least some of the energy added to the fluid is transferred to the barrel and the pump plunger, the pressure of the fluid increases, the walls of the barrel may elastically deform and expand outwardly due to the pressure increase, and the temperature of the fluid increases. Likewise, the pump plunger may also elastically deform resulting in an increased diameter.
However, since the barrel has greater mass than the pump plunger, and because it is immersed in the fluid, the barrel does not deform an equal amount as the pump plunger. Thus, as the pressure decreases on a return and filling stroke, the walls of the barrel may substantially return to their original configuration, while the pump plunger remains in an expanded state. Therefore, the pump plunger may rub or scuff the barrel on the return stoke, thereby reducing service life of the linearly actuated pump.
US Patent Application Publication US 2016/0222959 to Campion et al. (“Campion”) discloses a cryogenic piston pump with a barrel, a head with a bore, and a pump plunger slidably disposed within the bore. The pump plunger may be coated with tribological coating main layer, and a sacrificial break-in layer placed on the main layer that may also include a tribological coating, to thereby reduce rubbing, scuffing, and seizure of pump plungers and barrels.
The present disclosure is directed to overcoming one or more problems set forth above and/or other problems associated with the prior art.